Dynamic Analysis of Honeycomb Sandwich Beam with Multiple Debonds

Abstract EN

Analytical formulation for the evaluation of frequency of CFRP sandwich beam with debond, following the split beam theory, generally underestimates the stiffness, as the contact between the honeycomb core and the skin during vibration is not considered in the region of debond.

The validation of the present analytical solution for multiple-debond size is established through 3D finite element analysis, wherein geometry of honeycomb core is modeled as it is, with contact element introduced in the debond region.

Nonlinear transient analysis is followed by fast Fourier transform analysis to obtain the frequency response functions.

Frequencies are obtained for two types of model having single debond and double debond, at different spacing between them, with debond size up to 40% of beam length.

The analytical solution is validated for a debond length of 15% of the beam length, and with the presence of two debonds of same size, the reduction in frequency with respect to that of an intact beam is the same as that of a single-debond case, when the debonds are well separated by three times the size of debond.

It is also observed that a single long debond can result in significant reduction in the frequencies of the beam than multiple debond of comparable length.